Selectable friction assisted door holder assembly

Abstract: An adjustable overhead mounted door holder assembly (10) for attachment between a door jamb (14) and a door (12) to hold the door in an open position includes a jamb bracket (16) attached to the door jamb (14) and a jamb arm (18) pivotally attached to the jamb bracket (16). A channel assembly (22) having a longitudinally extending channel (23) is attached to the door, and a spring (42, 43) assisted assembly holds the door in an open position assisted by frictional force. The amount of friction is adjustable by altering a rotational position of an eccentric cam.

Description: This invention relates to an adjustable overhead door holder assembly and, more particularly, to a friction adjusted overhead mounted door holder assembly having a low profile suitable for mounting in a door top inset. Temporarily holding a door in an open position is often necessary for convenience and safety. One commonly employed method uses an overhead mounted door control device that includes a pivoting arm attached between an upper portion of a door jamb and an upper part of a door. When the door is to be held open at an angle that does not exceed about 110 degrees, an overhead mounted door control device is efficient, effective, convenient to install and maintain, is less subject to damage by vandalism or accidents and does not present a potential stumbling hazard. However, many conventional overhead mounted door control devices are difficult to mount in an inset door top properly because of their thickness. The time consuming and expensive modifications to the door required to properly fit the door holder can cause building managers to omit or postpone installation of door holders necessary for convenience or safety. Alternatively, marginal performance conventional low profile door holders may be attached, leading to dissatisfaction and high maintenance and replacement costs. What is needed is an overhead door holder assembly that is durable, easy to install as an inset into the top of a door, and adjustable or replaceable with minimal effort and expertise. The door holder should be set to permit easy engagement to hold the door against minor jostling contacts, and yet still permit closing the door without undue effort. In addition, the door hold position should be easily selectable and act at any angle of door opening. Such a door holder should not require special tools for installation or maintenance, and should have features to prevent damage from violent or forceful door opening. The door should automatically be held in an open position after it is swung open to a predetermined angle, and should allow for easy controllable release from its held open position when desired. US-A-1 573 456 relates to a friction controlled door holder assembly with features according to the preamble of claim 1. According to the present invention, there is provided an adjustable overhead mounted door holder assembly for attachment between a door jamb and a door, for selectively holding the door, comprising a jamb bracket for attachment to the door jamb; a jamb arm pivotally attached to the jamb bracket; a channel assembly having a channel therein defined by channel walls; a slide assembly positioned for movement in the channel, the slide assembly being adapted for pivotal attachment to the jamb arm and having at least one spring urging at least one friction pad against the channel wall and an adjustment assembly for varying friction force of said at least one friction pad against the channel wall; characterised in that there are two said springs respectively urging first and second friction pads against a respective channel wall and the adjustment assembly comprises a friction cam which is adjustable to vary compressive force of both springs, said friction cam being positioned between said first and second friction springs. The invention also extends to a door incorporating a door holder assembly essentially as just defined. For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:- Figure 1 is a perspective view of an adjustable overhead mounted door holder assembly that includes a channel assembly inset into a top of a door; Figure 2 is an exploded perspective view of a slide assembly, a channel assembly and a jamb arm; and Figures 3, 4 and 5 illustrate a slide assembly seated in a channel assembly, with a friction cam rotated to a different position in each of those Figures. As illustrated in Figure 1, an adjustable overhead door holder assembly 10 has a channel assembly 22 positioned in a door inset 20 at an upper edge 13 of a door 12. The channel assembly 22 is attached to the door 12 so that its longitudinally extending and generally U-shaped channel 23 is upwardly open. Positioned for sliding movement within the channel 23 is a slide assembly 26. The assembly 10 also includes a jamb bracket 16 permanently affixed to a door jamb 14. A jamb arm 18 is pivotally connected at one end to the jamb bracket 16 and at its opposite end to the slide assembly 26. In preferred embodiments, the jamb bracket 16, jamb arm 18 and channel assembly 22 are formed from brass or other durable, wear resistant material such as steel. When the door 12 is closed with its upper edge 13 positioned parallel to and adjacent to the door jamb 14, the slide assembly 26 is positioned in the channel 23 distant from the spring support 24. As the door 12 is opened, as shown in Figure 1, the pivoting connection of the jamb arm 18 between the jamb bracket 16 and the slide assembly 26 allows the slide assembly 26 to move along the channel 23 toward a spring support 24. When the door opening force is stopped or diminished, the static frictional force exerted by the slide assembly 26 against the channel walls holds the door in an open position at an infinitely selectable position from completely open to fully closed. As best illustrated in Figure 2, the slide assembly 26 includes a slider 36 having serrations 37 defined on it, first and second springs 42 and 43, first and second frictions pads 44 and 45 (formed from brake lining or other wear and heat resistant material), and a friction cam 38 connected to the slider 36 by its shaft 41 and a nut 40, along with additional locking engagement being provided by matched locking of its serrations 39 and serrations 37 of the slider 36. The springs 42 and 43 have a generally U-shaped cross sectional shape and are respectively positioned between the centrally located slider 36 and the first and second friction pads 44 and 45. When assembled, the springs 42 and 43 compress the pads 44 and 45 against the channel walls 21 of the channel assembly 22, the exact amount of compression being determined by the angle of rotation of the friction cam 38. As seen in Figures 3, 4 and 5, the friction cam 38 has an elliptical cross section. As the cam 38 is rotated from a first position with the long axis of the ellipse parallel to the channel (as seen in Figure 3) to an increasingly angled position with respect to the longitudinal axis of the channel assembly (Figures 4 and 5), the springs 42 and 43 are increasingly compressed. This compression of the springs 42 and 43 consequently results in greater static and dynamic frictional force exerted by the pads 43 and 44. Depending on the thickness, type of pad, door resistance, and other appropriate factors, the friction cam 38 can be adjusted to compress the springs a desired amount by adjusting its rotational angle. When the friction cam 38 is set at the correct rotational angle, it is slightly rocked so that the serrations 37 of the slider and serrations 39 of the friction cam 38 mesh, providing resistance to movement out of position as the nut 40 is tightened on the shaft 41. Using easily available tools, the present construction allows simple and quick adjustment of door hold force. An additional aspect of the present construction is the capacity for forceful door opening impact reduction. As best illustrated in Figures 3, 4 and 5, when the door is opened far enough, the slide assembly 26 impacts and is slowed by contact with springs 32 and 33 held by a spring support 24 to extend longitudinally in parallel spaced apart relationship along the channel 23. By slowly distributing the force of door opening, the springs prevent shock damage to the assembly 10. Both springs can have substantially equal spring constants and resistance to compressive force.

Claims: An adjustable overhead mounted door holder assembly (10) for attachment between a door jamb (14) and a door (12), for selectively holding the door, comprising a jamb bracket for attachment to the door jamb; a jamb arm pivotally attached to the jamb bracket; a channel assembly (22) having a channel (23) therein defined by channel walls; a slide assembly (26) positioned for movement in the channel, the slide assembly being adapted for pivotal attachment to the jamb arm (18) and having at least one spring (42, 43) urging at least one friction pad (44, 45) against the channel wall and an adjustment assembly for varying friction force of said at least one friction pad against the channel wall; characterised in that there are two said springs (42, 43) respectively urging first and second friction pads against a respective channel wall and the adjustment assembly comprises a friction cam (38) which is adjustable to vary compressive force of both springs, said friction cam being positioned between said first and second friction springs. An assembly according to claim 1, wherein said friction cam has an elliptical cross section. An assembly according to claim 1 or 2, wherein said friction cam further comprises a threaded shaft (41) held in locked position by a nut (40). An assembly according to claim 1, 2 or 3, wherein said slide assembly (26) further comprises a slider (36) having a plurality of serrations (37), and said friction cam (38) has a plurality of serrations (39) for locked engagement with the serrations on the slider. An assembly according to any one of the preceding claims, wherein each spring (42, 43) has a U-shaped cross section. An assembly according to any one of the preceding claims, wherein a spring support (24) is attached to the channel assembly (22) at a fixed position within the channel (23), with further springs (32, 33) being attached to the spring support to resist compressive force of the slide assembly (36) as the slide assembly approaches the spring support. An assembly according to claim 6, wherein said further springs (32, 33) are longitudinally positioned in the channel (23) in parallel, spaced apart relationship to each other, with both these springs having substantially equal spring constants and resistance to compressive force. A door holder assembly according to any one of the preceding claims, wherein the slide assembly further comprises a slider (36) having a plurality of serrations (37), and the friction cam (38) has a plurality of serrations (39) for locked engagement with the serrations on the slider, with the friction cam having a threaded shaft (41) that can be held in locked position by a separately attachable nut (40) after the serrations on the slider and the serrations on the friction cam are intermeshed in locking engagement. A door incorporating a door holder assembly according to any one of the preceding claims.

Inventors: COLEMAN MICHAEL D, COLEMAN, MICHAEL D.
Applicants: VON DUPRIN INC, VON DUPRIN, INC.
Application year: 1994
Main classification: E05C17
IPC codes: E05C17